U.S. patent application number 15/434673 was filed with the patent office on 2017-06-08 for method and system for service group management in a cable network.
The applicant listed for this patent is Maxlinear, Inc.. Invention is credited to Timothy Gallagher, Curtis Ling, Sridhar Ramesh.
Application Number | 20170163486 15/434673 |
Document ID | / |
Family ID | 49946480 |
Filed Date | 2017-06-08 |
United States Patent
Application |
20170163486 |
Kind Code |
A1 |
Ling; Curtis ; et
al. |
June 8, 2017 |
Method And System For Service Group Management In A Cable
Network
Abstract
A cable modem termination system (CMTS) may determine, for a
plurality of cable modems served by the CMTS, a corresponding
plurality of SNR-related metrics. The CMTS may assigning the modems
among a plurality of service groups based on the SNR-related
metrics. For any one of the modems, the CMTS may configure physical
layer communication parameters to be used by the one of the modems
based on a SNR-related metric of a service group to which the one
of the modems is assigned. The physical layer communication
parameters may include one or more of: transmit power, receive
sensitivity, timeslot duration, modulation type, modulation order,
forward error correction (FEC) type, and FEC code rate. The CMTS
and the modems may communicate using orthogonal frequency division
multiplexing (OFDM) over a plurality of subcarriers, and the
physical layer communication parameters may be determined on a
per-subcarrier basis.
Inventors: |
Ling; Curtis; (Carlsbad,
CA) ; Ramesh; Sridhar; (Carlsbad, CA) ;
Gallagher; Timothy; (Carlsbad, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Maxlinear, Inc. |
Carlsbad |
CA |
US |
|
|
Family ID: |
49946480 |
Appl. No.: |
15/434673 |
Filed: |
February 16, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15228703 |
Aug 4, 2016 |
9577886 |
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15434673 |
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13948444 |
Jul 23, 2013 |
9419858 |
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15228703 |
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61674742 |
Jul 23, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04L 43/08 20130101;
H04L 27/2602 20130101; H04L 41/0823 20130101; H04L 1/0009 20130101;
H04L 12/2801 20130101; H04L 43/12 20130101; H04L 1/0026 20130101;
H04B 17/318 20150115; H04L 27/2601 20130101 |
International
Class: |
H04L 12/24 20060101
H04L012/24; H04L 12/26 20060101 H04L012/26; H04L 12/28 20060101
H04L012/28; H04L 1/00 20060101 H04L001/00; H04L 27/26 20060101
H04L027/26 |
Claims
1. A method comprising: determining, by a cable modem termination
system (CMTS), for a plurality of cable modems served by said CMTS,
a corresponding plurality of signal-to-noise ratio (SNR) related
metrics; assigning, by said CMTS, said plurality of cable modems
among a plurality of service groups based on said plurality of
SNR-related metrics; generating, by said CMTS for each one of said
plurality of service groups, a composite SNR-related metric based
on a portion of said plurality of SNR-related metrics corresponding
to said one of said plurality of service groups; selecting, by said
CMTS, physical layer communication parameters to be used for
communicating with said one of said plurality of service groups
based on said composite SNR-related metric; and communicating, by
said CMTS, with a portion of said plurality of cable modems
corresponding to said one of said plurality of service groups using
said selected physical layer communication parameters.
2. The method of claim 1, wherein said physical layer communication
parameters include one or more of: transmit power, receive
sensitivity, timeslot duration, modulation type, modulation order,
forward error correction (FEC) type, and FEC code rate.
3. The method of claim 1, wherein said CMTS uses orthogonal
frequency division multiplexing (OFDM) over a plurality of
subcarriers for said communicating.
4. The method of claim 3, comprising selecting, by said CMTS, said
physical layer communication parameters on a per-OFDM-subcarrier
basis.
5. The method of claim 4, wherein said physical layer communication
parameters include one or both of: which of said OFDM subcarriers
to use for transmission to said CMTS, and which of said OFDM
subcarriers to use for reception of information from said CMTS.
6. The method of claim 1, wherein: said plurality of service groups
comprises a first service group and a second service group; said
first service group has a first composite SNR versus frequency
profile, said second service group has a second composite SNR
versus frequency profile, and a third cable modem has a particular
SNR versus frequency profile; and said assigning said plurality of
cable modems among said plurality of service groups comprises:
assigning said third cable modem to said first service group if
said particular SNR versus frequency profile is more similar to
said first composite SNR versus frequency profile than to said
second composite SNR versus frequency profile; and assigning said
third cable modem to said second service group if said particular
SNR versus frequency profile is more similar to said second
composite SNR versus frequency profile than to said first composite
SNR versus frequency profile.
7. The method of claim 1, comprising assigning said plurality of
cable modems among said plurality of service groups based on
distances between said CMTS and said plurality of cable modems.
8. The method of claim 1, comprising assigning any particular one
of said plurality of cable modems to one of said plurality of
service groups based on which one or more of a plurality of branch
amplifiers are upstream of said one of said plurality of cable
modems.
9. The method of claim 1, wherein said determining said plurality
of SNR-related metrics comprises: transmitting a probe message to
each said plurality of cable modems, said probe message comprising
instructions for measuring a metric and reporting said measured
metric back to said CMTS; and receiving a metric reporting message
from each of said plurality of cable modems.
10. A system comprising: circuitry for use in a cable modem
termination system (CMTS), said circuitry comprising a network
interface and a processor wherein: said processor is configured to
determine, for a plurality of cable modems served by said CMTS, a
corresponding plurality of signal-to-noise ratio (SNR) related
metrics; said processor is configured to assign said plurality of
cable modems among a plurality of service groups based on said
plurality of SNR-related metrics; said processor is configured to
generate, for each one of said plurality of service groups, a
composite SNR-related metric based on a portion of said plurality
of SNR-related metrics corresponding to said one of said plurality
of service groups; said processor is configured to select physical
layer communication parameters to be used for communicating with
said one of said plurality of service groups based on said
composite SNR-related metric; and said network interface is
configured to communicate with a portion of said plurality of cable
modems corresponding to said one of said plurality of service
groups using the selected physical layer communication
parameters.
11. The system of claim 10, wherein said physical layer
communication parameters include one or more of: transmit power,
receive sensitivity, timeslot duration, modulation type, modulation
order, forward error correction (FEC) type, and FEC code rate.
12. The system of claim 10, wherein said network interface and said
plurality of cable modems are configured to communicate using
orthogonal frequency division multiplexing (OFDM) over a plurality
of subcarriers.
13. The system of claim 12, wherein said network interface is
configured such that said physical layer communication parameters
are configurable on a per-OFDM-subcarrier basis.
14. The system of claim 12, wherein said physical layer
communication parameters include one or both of: which of said OFDM
subcarriers to use for transmission to said CMTS, and which of said
OFDM subcarriers to use for reception of information from said
CMTS.
15. The system of claim 10, wherein: said plurality of service
groups comprises a first service group and a second service group;
said first service group has a first composite SNR versus frequency
profile, said second service group has a second composite SNR
versus frequency profile, and a third cable modem has a particular
SNR versus frequency profile; said assignment of said plurality of
cable modems among said plurality of service groups comprises:
assignment of said third cable modem to said first service group if
said particular SNR versus frequency profile is more similar to
said first composite SNR versus frequency profile than to said
second composite SNR versus frequency profile; and assignment of
said third cable modem to said second service group if said
particular SNR versus frequency profile is more similar to said
second composite SNR versus frequency profile than to said first
composite SNR versus frequency profile.
16. The system of claim 10, wherein said processor is configured to
assign said plurality of cable modems among said plurality of
service groups based on distances between said CMTS and said
plurality of cable modems.
17. The system of claim 10, wherein said processor is configured to
assign said plurality of cable modems among said plurality of
service groups based on a branch further branch amplifier that
serves each of said plurality of cable modems.
18. The system of claim 10, wherein said determination of said
plurality of SNR-related metrics comprises: transmission, via said
network interface, of a probe message to each said plurality of
cable modems, said probe message comprising instructions for
measuring a metric and reporting said measured metric back to said
CMTS; and reception, via said network interface of said CMTS, of a
metric reporting message from each of said plurality of cable
modems.
Description
PRIORITY CLAIM
[0001] This patent application is a continuation of U.S. patent
application Ser. No. 15/228,703 filed on Aug. 4, 2016, which is a
continuation of U.S. patent application No. 13/948,444 filed on
Jul. 23, 2013, now Pat. No. 9,419,858, which makes reference to,
claims priority to and claims benefit from U.S. Provisional Patent
Application Ser. No. 61/674,742 titled "Method and System for
Service Group Management in a Cable Television Network" and filed
on Jul. 23, 2012.
[0002] The entirety of each of the above-mentioned applications is
hereby incorporated herein by reference.
INCORPORATION BY REFERENCE
[0003] This application also makes reference to: [0004] U.S. patent
application Ser. No. 13/553,328 titled "Method and System for
Client-Side Message Handling in a Low-Power Wide Area Network," and
filed on Jul. 19, 2012; [0005] U.S. patent application Ser. No.
13/485,034 titled "Method and System for Server-Side Message
Handling in a Low-Power Wide Area Network," and filed on May 31,
2012; [0006] U.S. patent application Ser. No. 13/553,175 titled
"Method and System for a Low-Power Client in a Wide Area Network,"
and filed on Jul. 19, 2012; [0007] U.S. patent application Ser. No.
13/553,195 titled "Method and System for Server-Side Handling of a
Low-Power Client in a Wide Area Network," and filed on Jul. 19,
2012; [0008] U.S. patent application Ser. No. 13/948,401 titled
"Method and System for a High Capacity Cable Network," and filed on
the same date as this application; and [0009] U.S. patent
application Ser. No. 13/948,417 titled "Method and System for Noise
Suppression in a Cable Network," and filed on the same date as this
application.
[0010] The entirety of each of the above-mentioned applications is
hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0011] Certain embodiments of the invention relate to cable
television networks. More specifically, certain embodiments of the
invention relate to a method and system for service group
management in a cable television network.
BACKGROUND OF THE INVENTION
[0012] Convention cable television networks can be inefficient and
have insufficient capacity. Further limitations and disadvantages
of conventional and traditional approaches will become apparent to
one of skill in the art, through comparison of such systems with
some aspects of the present invention as set forth in the remainder
of the present application with reference to the drawings.
BRIEF SUMMARY OF THE INVENTION
[0013] A system and/or method is provided for service group
management in a cable television network, substantially as shown in
and/or described in connection with at least one of the figures, as
set forth more completely in the claims.
[0014] These and other advantages, aspects and novel features of
the present invention, as well as details of an illustrated
embodiment thereof, will be more fully understood from the
following description and drawings.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
[0015] FIG. 1 is a diagram of an example cable/DOCSIS network.
[0016] FIG. 2A depicts an example method of determining locations
of CMs within the HFC network.
[0017] FIGS. 2B and 2C depict signal-to-noise ratio (SNR) versus
frequency profiles for an example cable/DOCSIS network.
[0018] FIG. 3A is a flowchart illustrating an example process for
configuring a cable/DOCSIS HFC network based on measured
performance metrics.
[0019] FIG. 3B is a flowchart illustrating an example process for
configuring a cable/DOCSIS HFC network based on location of CMs
within the network.
[0020] FIGS. 4A and 4B illustrate the network of FIG. 1, with
different groupings of CMs based on one or both of: measured
performance metric(s) and location within the HFC network.
DETAILED DESCRIPTION OF THE INVENTION
[0021] As utilized herein the terms "circuits" and "circuitry"
refer to physical electronic components (i.e. hardware) and any
software and/or firmware ("code") which may configure the hardware,
be executed by the hardware, and or otherwise be associated with
the hardware. As used herein, for example, a particular processor
and memory may comprise a first "circuit" when executing a first
one or more lines of code and may comprise a second "circuit" when
executing a second one or more lines of code. As utilized herein,
"and/or" means any one or more of the items in the list joined by
"and/or". As an example, "x and/or y" means any element of the
three-element set {(x), (y), (x, y)}. As another example, "x, y,
and/or z" means any element of the seven-element set {(x), (y),
(z), (x, y), (x, z), (y, z), (x, y, z)}. As utilized herein, the
term "exemplary" means serving as a non-limiting example, instance,
or illustration. As utilized herein, the terms "e.g.," and "for
example" set off lists of one or more non-limiting examples,
instances, or illustrations. As utilized herein, circuitry is
"operable" to perform a function whenever the circuitry comprises
the necessary hardware and code (if any is necessary) to perform
the function, regardless of whether performance of the function is
disabled, or not enabled, by some user-configurable setting.
[0022] FIG. 1 is a diagram of an example cable/DOCSIS network. The
example network comprises a cable modem termination system (CMTS)
102, a fiber node 104, amplifiers 106.sub.1-106.sub.3, a
directional coupler 108, splitters 110.sub.1-110.sub.3, and cable
modems (CMs) 112.sub.1-112.sub.5.
[0023] The CMTS 102 may comprise circuitry operable to manage
connections to the CMs 112.sub.1-112.sub.5. This may include, for
example: participating in ranging operations to determine physical
layer parameters used for communications between the CMTS 102 and
CMs 112.sub.1-112.sub.5; forwarding of dynamic host configuration
protocol (DHCP) messages between a DHCP server and the CMs
112.sub.1-112.sub.5; forwarding of time of day messages between a
time of day server and the CMs 112.sub.1-112.sub.5; directing
traffic between the CMs 112.sub.1-112.sub.5 other network devices
(e.g., Ethernet interfaces of the CMTS 102 may face the Internet,
Optical RF interfaces of the CMTS 102 may face the CMs, and the
CMTS may direct traffic between and among the Ethernet and Optical
RF interfaces); and managing registration of the CMs
112.sub.1-112.sub.5 to grant the cable modems network (e.g.,
Internet) access. The registration process for a CM 112.sub.X (X
between 1 and 5 for the example network of FIG. 1) may comprise the
CM 112 sending a registration request along with its configuration
settings, and the CMTS 102 accepting or rejecting the cable modem
based on the configuration settings. The registration process may
additionally comprise an exchange of security keys, certificates,
or other authentication information.
[0024] The fiber node 104 may comprise circuitry operable to
convert between optical signals conveyed via the fiber optic cable
103 and electrical signals conveyed via coaxial cable 105.
[0025] Each of the amplifiers 106.sub.1-106.sub.3 may comprise a
bidirectional amplifier which may amplify downstream signals and
upstream signals, where downstream signals are input via upstream
interface 107a and output via downstream interface 107b, and
upstream signals are input via downstream interface 107b and output
via upstream interface 107a. The amplifiers 106.sub.1, which
amplifies signals along the main coaxial "trunk" may be referred to
as a "trunk amplifier." The amplifiers 1062 and 1063 which amplify
signals along "branches" split off from the trunk may be referred
to as "branch" or "distribution" amplifiers.
[0026] The directional coupler 108 may comprise circuitry operable
to direct downstream traffic incident on interface 109a onto
interfaces 109b and 109c, and to direct upstream traffic incident
on interfaces 109b and 109c onto interface 109a. The directional
coupler 108 may be a passive device.
[0027] Each of the splitters 110.sub.1-110.sub.3 may comprise
circuitry operable to output signals incident on each of its
interfaces onto each of its other interfaces. Each of the splitters
110.sub.1-110.sub.3 may be a passive device.
[0028] Each of the cable modems (CMs) 112.sub.1-112.sub.5 may
comprise circuitry operable to communicate with, and be managed by,
the CMTS 1102 in accordance with one or more standards (e.g.,
DOCSIS). Each of the CMs 112.sub.1-112.sub.5 may reside at the
premises of a cable subscriber.
[0029] The components (including, fiber optic cables, coaxial
cables, amplifiers, directional couplers, splitters, and/or other
devices) between the CMTS and the CMs may be referred to as a
hybrid fiber coaxial (HFC) network. Any of the amplifiers,
directional coupler, and splitters may be referred to generically
as a coupling device.
[0030] FIG. 2A depicts an example method of determining locations
of CMs within the HFC network. As shown in FIG. 2A, to determine
one or more measured performance metric(s) (e.g., an SNR-related
metric such as SNR at a particular frequency or SNR over a range of
frequencies (an SNR profile), noise levels, strength of desired
signals, and/or the like) for any particular CM 112.sub.X, the CMTS
102 may transmit, at time 1, a message 202 that is destined
(unicast, multicast, or broadcast) for the CM 112.sub.X and that
functions as a probe to enable determination of the metric(s) for
the CM 112.sub.X. The message 202 may be sent on multiple channels
spanning multiple frequencies. Similarly, where OFDM is used for
communications between the CMTS 102 and the CM 112.sub.X, the
message 202 may be transmitted on each subcarrier, or may be sent
on a subset of subcarriers and then interpolation may be used for
determining the SNR of subcarriers on which the message 202 was not
sent.
[0031] The message 202 may be transmitted with such encoding,
modulation, and transmit power such that even a CM 112.sub.X with a
worst-case performance metric(s) can receive the message and
accurately measure the metric(s). In this regard, FIG. 2B shows a
SNR versus frequency graph for an example HFC network that uses
eight channels/subcarriers. The line 222 in FIG. 2B represents a
composite worst-case SNR profile for one or more CM(s) in the HFC
network to which the message 202 is destined. For example, line 222
may be a SNR profile for a single CM 112.sub.X to which the message
202 is to be unicast. As another example, the line 222 may be a
composite worst-case SNR profile for a plurality of CMs 112 of a
particular service group to which the message 202 is to be
multicast. As another example, the line 222 may be a composite
worst-case SNR profile for all CMs of an HFC network handled by the
CMTS 102 to which the message 202 is to be broadcast. The message
202 may be transmitted such that the minimum SNR needed to receive
and accurately measure the SNR profile is below the line 222 (e.g.,
SNR needed for receiving the message 202 may be the line 224).
[0032] Upon receipt of the message 202, a CM 112.sub.X may measure,
over the channels/subbands on which the message was sent, one or
more metrics (e.g., SNR versus frequency profile) for the
transmission 202. The CM 112.sub.X may then report the metrics(s)
back to the CMTS 102 via a message 204. In an example
implementation, the message 202 may contain information about when
and/or how the CM(s) are supposed to report their metric(s) (e.g.,
SNR profiles) back to the CMTS 102. In this regard, the message 202
may contain information that is the same as and/or or analogous to
what may be found in a MAP, UCD, and/or other MAC management
message defined in a DOCSIS standard. Accordingly, the message 202
may have specified a format of the message 204 and that the message
204 is to be transmitted at time T+.DELTA..
[0033] Once the metric(s) of one or more CMs are known to the CMTS
102, physical layer communication parameters to be used for
communications between the CMTS 102 and the CMs 112 may be
determined based on the metric(s). In this regard, physical layer
communication parameters may be determined per-CM based on each
CM's respective metric(s) (e.g., each CM's SNR profile),
per-service-group based on a composite metric(s) of the CM(s)
assigned to that service group (e.g., composite SNR profile for the
CM(s) of that service group), per physical region of the HFC
network based on a composite metric of the CMs located in that
physical region (e.g., composite SNR profile for the CM(s) in that
physical region), and/or the like. Furthermore, once the metric(s)
of a CM 112.sub.X is determined, the CMTS 102 may assign that CM
112.sub.X to one or more service groups based on its metric(s), as,
for example, described below with reference to FIG. 4A. Example
physical layer parameters include: encoding parameters, modulation
parameters, transmit power, receive sensitivity, timeslot duration,
channel(s) or subcarrier(s) on which to listen, channel(s) or
subcarrier(s) on which to transmit, and/or the like. Example
encoding parameters include: type of forward error correction (FEC)
to be used (e.g., Reed-Solomon, LDPC, etc.), FEC block size, FEC
code rate, etc. Example modulation parameters include: type of
modulation (e.g., frequency shift keying (FSK), phase shift keying
(PSK), quadrature amplitude modulation (QAM), etc.), modulation
depth, modulation order, etc.
[0034] In an example implementation, the transmission of messages
202, the calculation of metrics, such as SNR profile, by the CM(s),
the transmission 204, and subsequent configuration of physical
layer parameters based on the metric(s) may take place in parallel
with other operations performed during the registration/ranging
process.
[0035] Referring now to FIG. 2C, there is again shown the line 222
which represents the applicable SNR profile (e.g., an individual
SNR profile if configuring physical layer parameters per CM, a
composite SNR profile for a service group if configuring physical
layer parameters per service group, or a composite SNR profile for
a particular physical region). Also shown is a line 226
corresponding to SNR utilization for communications with the CM(s)
associated with the profile 222. Assuming the distance 228 is the
minimum desired headroom, then the physical layer communication
parameters resulting in line 226 are nearly optimal in the sense
that there is minimal headroom on each of channels/subbands 1, 3,
4, 6, 7, 8, and only slightly more than minimal headroom on
channels/subbands 2 and 5.
[0036] Physical layer parameters may be configured/coordinated
using upstream and/or downstream MAP messages, upstream channel
descriptors (UCDs), other MAC management messages defined in DOCSIS
protocols, and/or purpose-specific messages tailored to configuring
the parameters based on measured performance metrics such as SNR
profiles as described in this disclosure.
[0037] FIG. 3A is a flowchart illustrating an example process for
configuring a cable/DOCSIS HFC network based on SNR profiles. For
clarity of illustration the process is described with reference to
the network of FIG. 1 and the messages of FIG. 2A. The process
begins with block 302 in which the CMTS 102 sends one or more probe
messages 202 to the CMs 112.sub.1-112.sub.5. In block 304, each of
the CMs 112.sub.1-112.sub.5 determines its respective SNR profile
based on a received one of the messages 202, and reports the SNR
profile back to the CMTS 102 in the form of a message 204. In block
306, the CMTS 102 assigns the CMs to service groups based on the
SNR profiles.
[0038] In block 308, physical layer communication parameters are
determined per service group and per channel/subcarrier. For
example, for any particular service group, the modulation order and
FEC code rate to be used on a particular subcarrier may be
determined based on the worst case SNR for that subcarrier among
the CMs in that particular service group. Thus, it can be seen that
grouping CMs based on SNR profiles may enable configuring physical
layer communications parameters to such that one or more
communication parameters (throughput, reliability, etc.) is
optimal, or near-optimal, for all of the CMs in the service group.
For example, without such grouping by SNR profile, one CM in a
particular service group may have substantially lower SNR on one or
more channels/subcarriers. As a result, all CMs in that particular
service group may be forced to use physical layer parameters
supported by this "lowest common denominator" CM. This may result
in a lot of wasted capacity for the remaining CMs.
[0039] To illustrate with a specific example: assume that CMs
112.sub.1, 112.sub.4, and 112.sub.5 of FIG. 1 have sufficient SNR
on channel z to support 64-QAM on channel z, but that CMs 112.sub.2
and 112.sub.3 only have sufficient SNR on channel z to support
16-QAM. If 112.sub.1 is assigned to the same service group as
112.sub.2 or 112.sub.3, then 112.sub.1 may be forced to use 16-QAM
on channel z. Conversely, if 112.sub.1, 112.sub.4, and 112.sub.5
are assigned to a first service group and 112.sub.2 and 112.sub.3
are assigned to a second service group, then the first service
group consisting of 112.sub.1, 112.sub.4, and 112.sub.5 can use
64-QAM on channel z while the second service group consisting of
112.sub.2 and 112.sub.3 uses 16-QAM on channel z.
[0040] In block 310, communications between the CMTS 102 and any
particular service group use the per-service-group and
per-subcarrier/channel physical layer parameters determined in
block 308.
[0041] FIG. 3B is a flowchart illustrating an example process for
configuring a cable/DOCSIS HFC network based on location of CMs
within the network. For clarity of illustration, and as a
non-limiting example, the process is described with reference to
the network of FIG. 1 and the messages of FIG. 2B. The process
begins with block 322 in which the CMTS 102 determines a location
of each of the CMs 112.sub.1-112.sub.5 in the network. Location of
a CM 112.sub.X may be characterized in a variety of ways including,
for example: total distance of fiber and/or coaxial cable between
the CMTS 102 and the CM 112.sub.X, total attenuation between the
CMTS 102 and the CM 112.sub.X, which trunk amplifier(s) are
upstream of the CM 112.sub.X, how many coupling elements
(amplifiers, splitters, directional couplers, etc.) are between the
CMTS 102 and the CM 112.sub.X, GPS coordinates, and street address.
In block 324, the CMTS 102 assigns the CMs 112.sub.1-112.sub.5 to
service groups based on their determined locations. Blocks 326 and
328 are substantially similar to blocks 308 and 310, respectively,
of FIG. 3A.
[0042] The locations of the CMs 112.sub.1-112.sub.5 may be
determined by, for example, transmitting sounding signals into the
network. In order to characterize the channel with more precision,
the channel sounding signal may be sent repeatedly over an interval
of time and the CMs may average multiple measurements over the time
interval until they can resolve identifying characteristics in the
signal which indicate, for example, how many branch amplifiers
and/or other coupling elements that the signal traveled through to
reach the CM. In another example implementation, the CMTS may
communicate with a server that stores subscriber information that
associates the CMs with their geographic location (e.g., street
address).
[0043] While FIGS. 3A and 3B depict SNR profiles and location as
two separate bases on which to assign CMs to service groups, the
two may be used in combination.
[0044] FIGS. 4A and 4B illustrate the network of FIG. 1, with
different groupings of CMs based on one or both of: measured
performance metric(s) and location within the HFC network.
[0045] In the example of FIG. 4A, CMs 112.sub.1, 112.sub.4, and
112.sub.5 are assigned to service group 402 and CMs 112.sub.2 and
112.sub.3 are assigned to service group 404. The assignment of FIG.
4A may result from, for example, assigning CMs based on the number
of coupling elements between the CMTS 102 and the CMs--four each
for CMs 112.sub.1, 112.sub.4, and 112.sub.5; five each for CMs
112.sub.2 and 112.sub.3. The number of coupling elements may be
determined based on, for example, measured performance metrics
(e.g., SNR profile) of the CMs and/or address or GPS information
associated with the CMs. Alternatively, the assignment of FIG. 3A
may result from, for example, assigning the CMs to service groups
based directly on their respective measured performance metric(s)
(e.g., the extra device in the path between CMTS 102 and CMs
111.sub.2 and 112.sub.3 may cause CMs 112.sub.2 and 112.sub.3 to
have significantly poorer SNR).
[0046] In the example of FIG. 4B, CMs 112.sub.1, 112.sub.2, and
112.sub.3 are assigned to service group 406 and CMs 112.sub.4 and
112.sub.5 are assigned to service group 408. The assignment of FIG.
4B may result from, for example, assigning CMs based on which trunk
amplifiers are downstream of the CMs. Alternatively, the assignment
of FIG. 3A may result from, for example, assigning the CMs to
service groups based directly on their respective measured
performance metric(s) (e.g., the distance between CMTS 102 and CMs
112.sub.4 and 112.sub.5 may be substantially greater than the
distance between the CMTS 102 and the CMs 112.sub.1, 112.sub.2, and
112.sub.3, thus resulting in poorer SNR in CMs 112.sub.4 and
112.sub.5).
[0047] Grouping CMs according to which trunk or distribution
amplifiers are upstream of them may enable duty cycling power
branch and/or distribution amplifiers. For example, when a CM in
service group 406 is the talker, the upstream path through
amplifier 1062 may be disabled such that noise from group 408 does
not interfere with transmissions from the talker of service group
406. Grouping CMs according to which trunk or distribution
amplifier(s) serve(s) them may enable using more efficient physical
layer parameters. For example, where there is a relatively long
distance of cable between amplifier 106.sub.1 and 106.sub.2 but
relatively short distance of cable between amplifiers 106.sub.1 and
106.sub.3, grouping the CMs by geography/distance to the CMTS may
enable a lower transmit power to be used by the CMTS 102 when
talking to service group 406 as compared to when talking to service
group 408.
[0048] Other embodiments of the invention may provide a
non-transitory computer readable medium and/or storage medium,
and/or a non-transitory machine readable medium and/or storage
medium, having stored thereon, a machine code and/or a computer
program having at least one code section executable by a machine
and/or a computer, thereby causing the machine and/or computer to
perform processes described.
[0049] Accordingly, the present invention may be realized in
hardware, software, or a combination of hardware and software. The
present invention may be realized in a centralized fashion in at
least one computing system, or in a distributed fashion where
different elements are spread across several interconnected
computing systems. Any kind of computing system or other apparatus
adapted for carrying out the methods described herein is suited. A
typical combination of hardware and software may be a
general-purpose computing system with a program or other code that,
when being loaded and executed, controls the computing system such
that it carries out the methods described herein. Another typical
implementation may comprise an application specific integrated
circuit or chip.
[0050] The present invention may also be embedded in a computer
program product, which comprises all the features enabling the
implementation of the methods described herein, and which when
loaded in a computer system is able to carry out these methods.
Computer program in the present context means any expression, in
any language, code or notation, of a set of instructions intended
to cause a system having an information processing capability to
perform a particular function either directly or after either or
both of the following: a) conversion to another language, code or
notation; b) reproduction in a different material form.
[0051] While the present invention has been described with
reference to certain embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted without departing from the scope of the present
invention. In addition, many modifications may be made to adapt a
particular situation or material to the teachings of the present
invention without departing from its scope. Therefore, it is
intended that the present invention not be limited to the
particular embodiment disclosed, but that the present invention
will include all embodiments falling within the scope of the
appended claims.
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